The 4G USB Surfstick Huawei E398 USB dongle (Telekom 4G Speedstick LTE) is very similar to ZTE MF820 4G 100Mbps USB modem and Sierra Wireless Aircard 313U, they both support 4G LTE network but with different LTE frequencies. It is 3G & 2G Network backward compatible, it could be used on DC-HSPA+ 3G (2100MHz) and 2G where there is no 3G/4G coverage. In other words, you will always the fastest network, wherever you are.